DNA and You's Matt Mealiffe looks into the heritability of intraocular pressure -- a risk factor that eye doctors consider when screening patients for glaucoma. A recent article in the British Journal of Ophthalmology found by studying twins that genetics appears to explain about 62 percent of the eye pressure variation. Mealiffe adds that this study does not address a particular gene for congential glaucoma, though he points to others that have identified putative genes.